Trends in mortality, morbidity, and risk factor levels for stroke from 1960 through 1990. The Minnesota Heart Survey.

OBJECTIVE: The Minnesota Heart Survey is a population-based study designed to monitor and explain trends in cardiovascular mortality, morbidity, and risk factors.
DESIGN: Surveillance time-trends study.
METHODS: The following trends were examined among men and women aged 25 to 74 years living in Minneapolis-St Paul, Minn: (1) stroke mortality from 1960 through 1990; (2) risk factors in population-based surveys conducted in 1973 through 1974, 1980 through 1982, and 1985 through 1987; and (3) morbidity in a 50% sample of hospitalized discharges for acute-stroke in 1970, 1980, and 1985.
RESULTS: Stroke mortality in Minneapolis-St Paul declined slowly from 1960 through 1972 (average fall, 2.4% per year), dropped sharply from 1972 through 1984 (average fall, 6.5% per year), but exhibited little change thereafter (average fall, 1.5% per year). The average level of cardiovascular disease risk factors fell from 1973-1974 to 1985-1987, with the exception of body mass index. In particular, hypertension diagnosis, treatment, and control levels improved substantially between 1973-1974 and 1980-1982, although there was little improvement after 1980-1982. While discharge rates for hospital-coded acute stroke declined substantially between 1970 and 1985 in both sexes, no clear trend was observed in definite stroke rates as validated using standard clinical criteria. Twenty-eight-day case fatality rates of definite stroke improved significantly from 1970 to 1985.
CONCLUSIONS: The substantial decline in stroke mortality of more than 50% from 1960 through 1990 appears to have been attributable to both primary and secondary prevention. These data suggest that the long decline in stroke mortality and morbidity in Minneapolis-St Paul has plateaued, although improved detection of stroke with computed tomography prevents an unequivocal conclusion.